Laser Interferometric Monitor of Polymer Thin Film Properties During Device Fabrication
Original Publication Date: 1986-Oct-01
Included in the Prior Art Database: 2005-Mar-09
Disclosed is an in-situ and versatile process monitor which can measure thermal properties and thickness uniformities of transparent polymer films. The technique of laser interferometry allows one to non-destructively detect small changes in thickness and index of refraction of thin transparent films over reflective substrates from variations in the intensity of laser light reflected from those films [*]. Polymer properties which are relatable to changes in film thickness and/or refractive index include thermal expansion coefficient, stress level, drying/shrinkage rates, solvent intake/swelling/dissolution and thickness uniformity. Polymer films accessible with laser interferometry can be structures ranging in complexity from a single layer on a Si substrate to modules containing multiple levels of thin film wiring.